Chemie TBZ 1. Lehrjahr
Chapter 1,2 and 3
Chapter 1,2 and 3
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Cartes-fiches
About how many atoms of copper when placed side by side would form a line 1 cm long?
100 000 000
How is the atomic theory that is accepted today different from Dalton’s atomic theory?
Atoms are now known to be divisible. They can be broken down into even smaller more fundamental particles
Which subatomic particles carry a negative charge?
electrons
Thomson observed that the production of cathode rays did not depend on the kind of gas in the tube or the type of metal used for the electrodes. What conclusion did he draw from these observations?
He concluded that electrons must be parts of the atoms of all elements
The positively charged subatomic particle that remains when a hydrogen atom loses an electron is called
a proton
What charge does a neutron carry?
none
Explain why in 1911 Rutherford and his coworkers were surprised when they shot a narrow beam of alpha particles through a thin sheet of gold foil.
They expected most of the alpha particles to pass easily through the foil with only a
slight deflection. They found that most alpha particles were not deflected at all, and
a few were deflected at very large angles.
The total number of protons and neutrons in an atom is its?
mass numbers
What is the mass number of a helium atom that has two protons and two neutrons?
4
How many neutrons does a beryllium atom with four protons and a mass number of nine have?
5
Designate the atom shown in Question 25 in the form “name of element”-“mass number”.
neon 22
How do atoms of neon-20 and neon-22 differ?
An atom of neon 22 has two more neutrons in its nucleus that an atom of neon 20
Neon-20 and neon-22 are called?
isotopes
Is the following sentence true or false? Isotopes are chemically alike because they have identical numbers of protons and electrons.
true
Why is the atomic mass unit (amu), rather than the gram, usually used to express atomic mass?
The values of atomic masses measured in grams are inconveniently small and
impractical
What isotope of carbon has been chosen as the reference isotope for atomic mass units? What is the defined atomic mass in amu of this isotope?
carbon -12 12 amu
Is the following sentence true or false? The atomic mass of an element is always a whole number of atomic mass units.
false
In the periodic table, the elements are organized into groups based on
a set of repeating properties
What are the horizontal rows in the periodic table called?
periods
